Coverage for airflow/hooks/base_hook.py : 49%

# -*- coding: utf-8 -*- 

# 

# Licensed under the Apache License, Version 2.0 (the "License"); 

# you may not use this file except in compliance with the License. 

# You may obtain a copy of the License at 

# 

# http://www.apache.org/licenses/LICENSE-2.0 

# 

# Unless required by applicable law or agreed to in writing, software 

# distributed under the License is distributed on an "AS IS" BASIS, 

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

# See the License for the specific language governing permissions and 

# limitations under the License. 

from __future__ import absolute_import 

from __future__ import division 

from __future__ import print_function 

from __future__ import unicode_literals 

from builtins import object 

import logging 

import os 

import random 

from airflow import settings 

from airflow.models import Connection 

from airflow.exceptions import AirflowException 

CONN_ENV_PREFIX = 'AIRFLOW_CONN_' 

class BaseHook(object): 

""" 

Abstract base class for hooks, hooks are meant as an interface to 

interact with external systems. MySqlHook, HiveHook, PigHook return 

object that can handle the connection and interaction to specific 

instances of these systems, and expose consistent methods to interact 

with them. 

""" 

def __init__(self, source): 

pass 

@classmethod 

def get_connections(cls, conn_id): 

session = settings.Session() 

db = ( 

session.query(Connection) 

.filter(Connection.conn_id == conn_id) 

.all() 

) 

if not db: 

raise AirflowException( 

"The conn_id `{0}` isn't defined".format(conn_id)) 

session.expunge_all() 

session.close() 

return db 

@classmethod 

def get_connection(cls, conn_id): 

environment_uri = os.environ.get(CONN_ENV_PREFIX + conn_id.upper()) 

conn = None 

if environment_uri: 

conn = Connection(conn_id=conn_id, uri=environment_uri) 

else: 

conn = random.choice(cls.get_connections(conn_id)) 

if conn.host: 

logging.info("Using connection to: " + conn.host) 

return conn 

@classmethod 

def get_hook(cls, conn_id): 

connection = cls.get_connection(conn_id) 

return connection.get_hook() 

def get_conn(self): 

raise NotImplementedError() 

def get_records(self, sql): 

raise NotImplementedError() 

def get_pandas_df(self, sql): 

raise NotImplementedError() 

def run(self, sql): 

raise NotImplementedError()